1. Field of the Invention
The present invention relates to a scroll compressor enabling to prevent the breakage of a scroll by coping suitably with a volume variation working in a radial direction of a compressing chamber as well as improve a reliance of the compressor.
2. Background of the Related Art
Generally, a scroll compressor is an apparatus of compressing a fluid by varying a volume of a compressing chamber formed by a pair of scroll compressors. Compared to a reciprocating compressor or a rotary compressor, the scroll compressor has a high efficiency as well as a low noise. And, the light-weighted and small-sized scroll compressor can be manufactured, thereby enlarging its applied fields gradually.
FIG. 1 illustrates a cross-sectional view of a scroll compressor according to a related art, and FIG. 2 illustrates a magnified cross-sectional view of a part xe2x80x98Axe2x80x99 on FIG. 1.
Referring to FIG. 1, a scroll compressor according to a related art includes a casing 106 having a hermetic space wherein a suction pipe 102 sucking a fluid and a discharge pipe 104 discharging a compressed fluid are connected to an upper side and a lateral side, respectively, a driving unit 108 arranged at lower side of the casing 106 so as to generate a driving power, and a compressing unit 112 arranged at the upper side of the casing 106 and connected to the driving unit 108 and a crankshaft 110 so as to carry out a compression of a fluid.
The driving unit 108 includes a stator 114 fixed in a circumferential direction of the casing 106 and a rotor 116 arranged at an inner circumference face of the stator 114 so as to be fixed to the crankshaft 110. Once an electric power is applied to the stator 114, the crankshaft 110 revolves by a reciprocal reaction between the stator 114 and rotor 116.
The compressing unit 112 includes a fixed scroll 120 having an involute fixed wrap 118 and connected to the suction pipe 102 so as to be connected to the upper side of the casing 106 and an orbiting scroll 124 having an involute orbiting wrap 122 corresponding to the fixed wrap 118 so as to be connected to the crankshaft 110 eccentrically, wherein a uniform compressing chamber is provided between the fixed and orbiting scrolls 120 and 124.
The crankshaft 110 is supported by a main frame 128 fixed to the upper side of the casing 106 so as to revolve. An eccentric part 132 inserted in a boss 130 of the orbiting scroll 124 to make the orbiting scroll 124 circle round is formed at the upper side of the crankshaft 110. And, an oil flow path 134 is formed in a shaft direction so as to supply a frictional part between the orbiting scroll 124 and the eccentric part 132 with the oil filling the lower side of the casing 106.
A back pressure chamber 136 is formed between the main frame 128 and orbiting scroll 124 so as to forming a medium pressure between sucking and discharging pressures generated from inflow and outflow of the compressed fluid. And, an Oldham ring 138 is installed at a lower face of the orbiting scroll 124 so as to prevent the rotation of the orbiting scroll 124.
A seal ring 140 is inserted between the eccentric part 132 of the crankshaft 110 and the boss 130 of the orbiting scroll 124 so as to prevent the oil sucked through the oil flow path 134 from flowing out to the back pressure chamber 136.
Operation of the above-constructed scroll compressor according to a related art is explained as follows.
Once the electric power is applied to the driving unit 108, the crankshaft 110 connected to the rotor 116 starts revolving. And, the eccentric part 132 revolves so as to make the orbiting scroll 124 circle round. The fluid having flowed in the compressing chamber 126 through the suction pipe 102 moves to be compressed to a central part of the compressing chamber 126 by the circling movement of the orbiting scroll 124, and then the compressed fluid is discharged inside the casing 106 through a discharge outlet 142. The fluid discharged through the discharge outlet 142 at high pressure is discharged externally through the discharge pipe 104 connected to the lateral side of the casing 106.
When the fluid discharged inside the casing 106 at the high pressure pressurizes the oil stored in the lower side of the casing 106, the pressurized oil is supplied between the boss 130 of the orbiting scroll 124 and the eccentric part 132 along the oil flow path 134 so as to carry out a lubrication as well as pressurizes the orbiting scroll 124 upward so as to maintain a close adherence between the orbiting and fixed wraps 112 and 118.
In this case, a cross-sectional area of the eccentric part 132 is made to be equal to that of the crankshaft 110 so that there occurs no load in a shaft direction. Namely, a pressure of the oil pressurizing the eccentric part 132 downward is equal to that of the fluid pressurizing the crankshaft 110 upward, thereby the load fails to work on the crankshaft 110 in the shaft direction.
Unfortunately, the above-explained scroll compressor according to the related art has the crankshaft and eccentric part of which cross-sectional areas are equal to each other as well as the orbiting scroll fails to move in a radial direction. When a incompressible fluid such as a liquefied refrigerant, oil or particles flows in the compressing chamber so as to increase an inner pressure of the compressing chamber abnormally, a volume of the compressing chamber fails to vary in the radial direction. Therefore, the orbiting and fixed wraps of the orbiting and fixed scrolls are broken as well as a torsion stress is concentrated on the driving unit or crankshaft.
Accordingly, the present invention is directed to a scroll compressor that substantially obviates one or more problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a scroll compressor coping properly with a volume variation of a compressing chamber due to an inflow of an incompressible fluid or the like by installing a radial moving apparatus enabling an orbiting scroll to move radially between an eccentric part of a crankshaft and the orbiting scroll so as to prevent the breakage of the scroll and improve a reliance of the compressor.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a scroll compressor according to the present invention includes a casing having a high pressure inside, a driving unit arranged at a lower side of the casing and connected to a crankshaft so as to generate a driving force, a compressing unit having an orbiting scroll connected to the crankshaft eccentrically and a fixed scroll so as forming a compressing chamber between the orbiting and fixed scrolls, and a compliance means for retreating the orbiting scroll in a radial direction when an incompressible material flows in the compressing chamber, the compliance means installed between the compressing unit and the crankshaft.
Preferably, an oil flow path is formed to penetrate the crankshaft in a length direction and an eccentric part is formed at an upper side of the crankshaft so a to have a cross-sectional area smaller than that of the crankshaft.
More preferably, the compliance means is a compliance member inserted in an inner circumference face of a boss formed at a lower face of the orbiting scroll so as to revolve, a slot penetrates a center of the compliance member, and the eccentric part of the crankshaft is inserted in the slot so as to slide to move.
More preferably, the eccentric part extends from an upper side of the crankshaft so as to form a predetermined step part and has a straight portion provided by cutting both sides of the eccentric part 16 in a length direction.
More preferably, the slot is formed to have a predetermined length in a long direction so that the straight portion of the eccentric part is inserted in the slot to slide and the eccentric part slides to move in a radial direction to a predetermined distance.
More preferably, a seal ring is installed between an outer circumference face of the compliance member and the inner circumference face of the boss of the orbiting scroll.
More preferably, a cross-sectional area of the crankshaft is equal to an outer diameter area of the compliance member.
More preferably, a flange unit protrudes from an upper face of the crankshaft to a predetermined width in an external direction.
More preferably, a rib is formed in an outer circumferential direction of a lower face of the compliance member so as to adhere closely to an upper face of the crankshaft.
More preferably, a rib is formed in an inner circumferential direction of a lower face of the compliance member so as to adhere closely to an upper face of the crankshaft.
More preferably, a sealing member is inserted between a lower face of the compliance member and an upper face of the crankshaft.
More preferably, a fitting groove is formed at the lower face of the compliance member in a circumferential direction so that the sealing member fits in the fitting groove.
More preferably, a fitting groove is formed at the upper face of the crankshaft in a circumferential direction so that the sealing member fits in the fitting groove.
More preferably, the sealing member is formed of a Teflon based material.
More preferably, an elastic body is connected between an inner circumference face of the compliance member and an outer circumference face of the eccentric part of the crankshaft.
More preferably, the elastic body is a coil spring.
Preferably, the compliance means is a compliance member inserted in a boss formed at a lower face of the orbiting scroll to revolve and having an eccentric hole formed eccentric from a center so that an eccentric part of the crankshaft is inserted in the eccentric hole.
More preferably, the eccentric part is cylindrical so as to extend from an upper face of the crankshaft.
More preferably, the compliance member is cylindrical so as to be inserted in an inner circumference face of the boss and wherein an eccentric hole is formed at a location eccentric from a center of the compliance member to a predetermined extent.
It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.